The soundtouch 20 does not turn on, progress bar stay at bottom.

My speaker could not connect to the soundtouch app, so i've done a firmware upgrade. Unfortunately during of this method the installing was stucked out. After that I can not turn on, I can not use it. The hard reset, soft reset can not work, and the firmware upgrad can not be started again. The progress bar stay at bottom (stay empty).

I hope somebody could help with this issue.

Thank you for your help in advance!

Janos